Apparatus for the production of dry prints by the silver salt diffusion process



Feb. 8, 1966 G. SCHAUM ETAL 3,233,534

APPARATUS FOR THE PRODUCTION OF DRY PRINTS BY THE SILVER SALT DIFFUSION PROCESS Filed Sept. 4, 1962 2 Sheets-Sheet 1 FIG. 7

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INVENTORS: Gustav Schaum, Werner Liebe, GUnther SteinbiJchel BY 67M MEAN WORN Y5 Feb. 8, 1966 G. SCHAUM ETAL 3,233,534

APPARATUS FOR THE PRODUCTION OF DRY PRINTS BY THE SILVER SALT DIFFUSION PROCESS Filed Sept. 4, 1962 2 Sheets-Sheet 2 INVENTORS: Gustav Schaum, Werner Liebe, Giinther SfeinQuchel Mix. "61;; AT T ORNE Y5 K United States Patent Germany Filed Sept. 4, 1962, Ser. No. 221,091 Claims priority, application Germany, Sept. 11, 1961,

2 Claims. (cl. 9s--s9) This invention relates to an apparatus for the production of prints by the silver salt diffusion process, and more particularly to an apparatus by means of which substantially dry prints are obtained.

In the silver salt diffusion process the imagewise exposed silver halide emulsion layer of a photographic sheet material (negative) is developed while in close contact with the non-lightsensitive colloid layer of a transfer material (positive) by means of a silver halide developing solution containing a silver halide solvent to produce a negative image of the master to be reproduced in the negative and a positive image of said master in the positive. Thereafter the two sheet materials are peeled apart.

For carrying out this process both negative and positive were hitherto passed through the developer solution and then passed through a squeegee device where both sheets were brought into satisfactory contact and excess developer was held back. The prints which are thus obtained are very moist and must first be laid out to dry. This dry ing is very tedious in the production of a relatively large number of prints. A further disadvantage consists in the relatively large quantity of developer which is needed because of the length of developer bath necessary for imbibing the silver salt difiusion materials. These relatively large quantities of developer can easily oxidize and become useless if they stand in the apparatus for a long time.

It is known to moisten a negative material for the silver salt diffusion process, on the emulsion side only, by means of an applying roller which runs in the developer tank, while the positive remains quite dry. As a result of the applying roller running in a large developer tank, however, a relatively large amount of air is introduced into the developer so that it very rapidly oxidizes and so becomes useless very quickly.

The present invention now relates to an apparatus for the production of prints by the silver salt diffusion process of the type having an applying roller for Wetting only the emulsion coating of the negative with developer, wherein the positive is conveyed, dry, below the developer tank to a pair of squeegee rollers. The apparatus is designed in such a manner that the applying roller runs in a very small developer tank having a small amount of developer therein, which tank is connected to a storage container in such a manner that the level of the liquid in the developer tank is always maintained constant and the developer runs back into the storage container simply by tilting the apparatus after use. The apparatus permits, in a simple manner, the installation of a storage container or a magazine roll for the positive from which material can be taken as required.- As a result, the following improvements are obtained:

(1) The print comes out of the apparatus almost dry and no longer needs to be laid out to dry.

(2) Only a little developer is used which can be quickly and easily returned to a storage container and so does not become useless.

(3) The surface of the developer, which comes into contact with air, is very small, so that the developer only becomes inactive slowly if it stands in the apparatus.

3,233,534 Patented Feb. 8, 1966 The structural principle of the apparatus will be briefly explained with reference to the accompanying drawings. FIGURES 1 and 3 of which represent two difierent modications of the apparatus in cross-section, FIGURE 2 represents the apparatus according to FIGURE 1 in elevation and FIG. 4 is a broken-away detail view of a portion of the apparatus of FIG. 1.

An applying roller 1 which consists of a non-absorbent material has a surface which is smooth or may be provided with grooves in order to pick up more developer liquid. The roller 1 runs in a very small developer tank 2 which contains only about 20 to 200 ml. of developer 3.

This developer tank is in communication, in the manner of a chicken fountain" (see FIG. 4) with a storage container 4 as a result of which the level of developer in the developer tank always is maintained constant. A semicircular sleeve 6 which is about 2 to 3 cm. wide is provided above the connecting passage 5 and has the effect that when the apparatus is tipped up the developer collects here and runs back into the storage container through the connecting passage 5. The sleeve ends engage the trough edges so that the sleeve and trough together form a container for fluid around the passage 5, as clearly shown in FIGS. 1 and 3.

The applying roller 1 runs at a higher speed of rotation than the squeegee rollers 7 so that suflicient fresh developer is always applied to the negative N. The direction of rotation may be the same or opposite to the direction of travel of the negative. A cover 8 covers the applying roller and serves simultaneously as a guide member for the negative. The motor 7a drives one of the squeegee rollers 7 and the applying roller 1.

An inclined supporting surface 9 leads to the applying roller and the negative is guided by this surface tangentially on to the applying roller. The moistened negative material is then conveyed to the squeegee rollers 7 over a second inclined supporting surface 10.

Whereas the feed plate 9 is fitted directly to the developer bowl, the delivery plate 10 is provided about 0.5 cm. above the developer tank so that a slot 11 is formed. A plate 12 runs from the developer tank parallel to the delivery plate at a distance therefrom of the width of the slot. This device serves to catch the developer which may be wiped from the negative at the front edge of the delivery plate 10 and which then runs down on the under side of the supporting surface, to convey it back into the developer tank. The positive P is conveyed dry, between guide members 13 and 14 below the developer tank and is first brought together with the moist, developed negative in front of the squeegee rollers 7. The guide members for the positive are preferably formed from narrow strips.

The structural principle of the so-called chicken fountain is apparent from FIGURE 4. The designations have the same meaning as described above. In this arrangement, the level of liquid in tank 2 is maintained constant since spent liquid is automatically replenished by fresh liquid from container 4 through passageway 5.

It is also possible to provide a sheet dispenser under the developer tank as shown in FIGURE 3, from which dispenser the positive material is taken as required.

What we claim is:

1. In a developing-transfer apparatus for passing a sheet of photographically exposed material for moist processing, and having a trough that holds only a small quantity of processing liquid inadequate for sustained use, and a reservoir for additional processing liquid being rigidly connected for supplying more liquid to the trough, the improvement comprising passageway means connecting the reservoir to the trough for automatically defining the level of liquid supplied to the trough, and

liquid confining means including a wall disposed above said passageway means with the ends of said wall engaging said trough for guiding liquid from the trough back to the reservoir when the apparatus is tilted in that direction.' 8

2. In a developing-transfer apparatus for passing a sheet of photographically exposed material for processing, and having a roller arranged to moisten one face of the passing sheet, the roller being-partially immersed in a close-fitting trough that holds only a small quantity of processing liquid inadequate for sustained use, and a reservoir of additional processing liquid being rigidly connected .for supplying more liquid to the trough, the improvement comprising passageway means connecting the reservoir to the trough for automatically defining the level of the liquid supplied to the trough, and liquid confining means including a wall disposed above said passageway means with the endsof said wall engaging said trough for guiding liquid from the trough back to the reservoir when the apparatus is tilted in that direction.

UNITED STATES PATENTS 2,605,684 8/1952 Nagels et a1. 9589 5 2,762,281 9/1956 Kleinstra a 95-89 3,031,942 5/1962 Carlson 95 -s9 FOREIGN PATENTS 699,085 10/ 1953 Great Britain. 768,659 2/1957 Great Britain. 10 338,703 7/1959 Switzerland.

OTHER REFERENCES German Application, No. 1,093,671, printed November 24, 1960. 15

NORTON ANSHER, Primary Examiner.

EMEL G. ANDERSON, Examiner. 

1. IN A DEVEOPING-TRANSFER APPARATUS FOR PASSING A SHEET OF PHOTOGRAPHICALLY EXPOSED MATERIAL FOR MOIST PROCESSING, AND HAVING A TROUGH THAT HOLDS ONLY A SMALL QUANTITY OF PROCESSING LIQUID INADEQUATE FOR SUSTAINED USE, AND A RESERVOIR FOR ADDITIONAL PROCESSING LIQUID BEING RIGIDLY CONNECTED FOR SUPPLYING MORE LIQUID TO THE TROUGH, THE IMPROVEMENT COMPRISING PASSAGEWAY MEANS CONNECTING THE RESERVOIR TO THE TROUGH FOR AUTOMATICALLY DEFINING THE LEVEL OF LIQUID SUPPLIED TO THE TROUGH, AND LIQUID CONFINING MEANS INCLUDING A WALL DISPOSED ABOVE SAID PASSAGEWAY MEANS WITH THE ENDS OF SAID WALL ENGAGING SAID TROUGH FOR GUIDING LIQUID FROM THE TROUGH BACK TO THE RESERVOIR WHEN THE APPARATUS IS TILTED IN THAT DIRECTION. 